Apparatus for drawing textile filaments



M h 1 1964 E. P. BRIGNAC ETAL 3,123,891 APPARATUS FORDRAWING TEXTILE FILAMENTS Filed April 10, 1961 nwszvroz 5040410 I? BRIG 0BERT 7. IVRIGIIT ArroRA/Ey United States Patent 3,123,891 APPARATUS FOR DRAWING TEXTILE FILAMENTS Edmond Paul Brignac, Pensacola, and Robert T. Wright,

Gulf Breeze, Fla., assigrrors, by mesne assignments, to

Monsanto Chemical Company, a corporation of Delaware Filed Apr. 10, 1961, Ser. No. 102,053 3 Claims. (Cl. 2871.3)

This invention relates to apparatus for longitudinally forwarding textile filaments. More particularly, this invention relates to apparatus for stretching continuous textile filaments employing a novel draw roll.

Freshly spun synthetic polymeric filaments exhibit low strength. To increase the strength thereof it has been found advantageous to stretch the filaments under various conditions whereby the polymer molecules are aligned in the direction of filament axis. Higher strength demands of recent date have resulted in the filaments being stretched to a greater extent. Unfortunately, as one increases the degree of stretch and maintains high feed rates, the yarn quality diminishes when the heretofore known stretching apparatus are employed. The lower quality is manifested in greater whole threadline breakages and individual filament breakages within the threadline.

In the drawing of filaments a stretching assembly including a pair of feed rolls and a draw roll, together with an associated separator roller, is conventionally used. The peripheral speed of the draw roll in relation to the peripheral speed of the feed roll is adjusted such that the filaments are stretched the desired extent. The draw roll causes the filaments being supplied to it to be under considerable tension. To prevent slippage of the filaments around the draw roll and the separator roll, it has been found that several wraps therearound are necessary. The efiiciency of the drawingoperation, as well as the yarn quality, depends to a large extent upon the character of the surface of the draw roll. -In general, there are two types of surfaces in use, each having special advantages and disadvantages. One type of surface is known as a mirror surface obtained by polishing the surface of a metal roll so that it has practically no roughness. The other type of surface is known as a matte surface and is roughened such as by impinging an abrasive against the surface. gripped more by the filaments; and accordingly, less wraps around the draw roll are required to stretch the filaments. However, there is an undesirable tendency for the filaments to cling to the surface of the roll. Vlhen the filaments leave the roll and are directed therefrom, individual filaments flit or flutter at the point of withdrawal, since the filaments will tend to follow the periphery of the roll. rise to filament breaking and causes a reduction in yarn quality.

With a draw roll having a matte surface the filaments can be moved from the roll satisfactorily, and there is less flitting of the filaments. However, rolls with a matte surface are generally unsatisfactory from a slippage standpoint.

It is an object of the present invention to provide new and improved apparatus for drawing textile filaments.

Another object of the present invention is to provide a draw roll assembly comprising a driven roll and an associated separator roll, said driven roll having a particular surface whereby textile filaments can be placed under considerable tension in an effective manner while maintaining satisfactory filament quality.

ther objects will become apparent from the following detailed description.

The smoothmirror surface is' This fugitive wrapping tendency givesgreater than percent polished surface area, the quality of the drawn filaments notably diminishes in that the fila-" 3,123,891 Patented Mar. 10, 1964 The objects in general are accomplished in the provi sion of novel apparatus adapted to draw textile filaments. The apparatus comprises means to supply textile filaments from a source at a predetermined speed and a metal cylindrical draw roll adapted to be driven so that the filaments normally being supplied to it are under considerable tension. The draw roll carries a plurality of polished surface strips and a plurality of roughened surface strips on the yarn engaging peripheral area thereof. The strips are substantially parallel and extend axially of the draw roll with the polished strips and the roughened strips following one another consecutively about the periphery of the draw roll. The total surface area of the polished strips constitutes 5080 percent of the total yarn engaging peripheral area of the draw roll. A separator roll is mounted adjacent the said draw roll in spaced relationship therewith and is positioned so that the axis of the separator roll is disposed at a slight angle with respect to the axis of the draw roll in order that the filaments normally progressing around the draw roll and the separator roll will describe generally a helix, the convolutions of which are spaced apart.

In the accompanying drawing an apparatus with principal parts in location suitable for practicing the present invention is shown.

In the drawing numeral 10 represents generally a feed roll assembly which is adapted to supply filaments 11 from a source. As illustrated the feed roll assembly comprises two rotatably mounted rolls 12 and 13, at least one of which is positively driven. Roll 13 is connected with a drive motor 14 so that it is driven with the roll 12 being an idler roll. The rolls engage each other so that the filaments are nipped sufficiently that they do not slip therethrough when tensioned in the yarn path beyond the two rolls.

A draw roll 15 is rotatably mounted on shaft 16. Connected with this shaft is a motor 17 which drives the roll 15 at a predetermined speed. The surface of the roll 15 is provided with a plurality of strips 18 which extend axially of the rolls and are substantially parallel to each other. Strips 18 are roughened to have What is called a matte finish. Such finish can be obtained by blasting an abrasive against the portions of the rolls, which are to be roughened. The blasting produces craters and irregular ridges therebetween. The depth of the craters may be in the range of about 20 to microinches and the width thereof may be in the range of 0.0005 to 0.005 inch. Positioned sequentially between roughened strips 18 are polished strips 19. The polished strips may be regarded as having a mirror finish which can be obtained by polishing the metal roll in a conventional manner. The length of the strips 18 and 19 may vary but are sufficient that multiple passes of the filaments can be made therearound Without superpositioning thereof. The number of passes around the roll is determined by the roll size and the amount of tension required on the filaments between the feed roll assembly and the roll 15.

use at least three strips of each kind for a total of 6 While there is no definite upper limit as to the strips. number of strips, it is preferred that no more than 12 strips of each kind be used per roll. Where the roll has The number of polished 3 ments tend to stick to the wrap. To overcome the tendency the filaments where they are removed from the roll are quickly jerked so that the filaments appear to be flitting or fluttering at the point of withdrawal. The jerking causes broken filaments and increases the likelihood of threadline breakage.

A separator roll 20, preferably of much smaller diameter is associated with draw roll 16. The axis of roll 20 is at an angle with respect to the axis of roll to provide longitudinal advancement of the filaments. Ordinarily, roll is freely rotatably mounted and is positioned adjacent to draw roll 15. Roll 15 is adapted to be rotated at a rate such that its peripheral speed exceeds the peripheral speed of rolls 12 and 13 so that the filaments are stretched a predetermined amount.

When synthetic filaments are stretched to increase the molecular orientation thereof, the transition from the unstretched segment to the stretched segment takes place on a relatively short length of the filaments. This area of transition is termed the point of necking down. To produce filaments of more uniform quality, it is often desirable to localize the necking down point. This may be accomplished by the use of a snubbing pin, or roll or the like. Accordingly, it is advantageous to employ such snubbing means in the yarn path for the same purpose. In the embodiment illustrated in the drawing a snubbing pin 21 is mounted in the yarn path so as to be non-rotative and over which the filaments are wrapped a desired number of times. After being drawn the filaments are taken up in an orderly manner such as by the use of a conventional winder, ring twister, or the like.

In operation, filaments 11 are led through the nip of rolls 12 and 13 which are driven at a predetermined peripheral speed. Next, the filaments are wrapped around pin 21 and then a suitable number of times around the stripped roll 15 and its associated roll 20. Roll 15 is driven so that the filaments before reaching the roll 15 are under considerable tension. The filaments can be tensioned with a minimum number of wraps being required to be taken around the roll 15 and separator roll 20 to prevent slippage therearound. Also, the flicking of the filaments at the point where they are removed tangentially from roll 15 is minimized.

The apparatus of the present invention is applicable to processing a wide variety of filaments and yarns. The filaments can be made from a thermoplastic fiber-forming resin and can be extended by drawing and then show increased molecular orientation along the filament axis. Examples of fiber-forming synthetic polymers are polyethylene; polypropylene; polyurethanes; copolymers of vinyl acetate and vinyl chloride; the copolymers of vinylidene and a minor proportion of mono-olefinic compounds copolymerized therewith; homopolymers of acrylonitrile, copolymers of acrylonitrile and a minor proportion of at least one mono-olefinic compound copolymerized therewith and polymer blends containing combined acrylonitrile in a major proportion; copolymers of vinyl chloride and acrylonitrile; linear polyesters of aromatic dicarboxylic acids and dihydric compounds such as polymeric ethylene terephthalate and the polyester derived from terephthalic acid and bis-1.4(hydroxymethyl) cyclohexane; linear polycarbonamides (nylons) such as, for example, nylon 66, nylon 4, nylon 6, nylon 610, nylon 11 and their fiber-forming copolymers thereof.

While the apparatus is suitable for the treatment of yarn whose filaments have a normal cross-section such as that produced where a spinneret having circular shaped orifices is employed during the manufacture therof, better processing of yarn having a multi-lobal cross section can be attained than with known apparatus. Multi-lobal yarn may be regarded as having a body section and a plurality of fins or legs integrally joined to the body section and radially extending therefrom, such as yarn of X or Y- shaped cross section. It has been found that the legs of the Inulti-lobal filaments when passed over the draw roll spread out, thereby giving rise to a larger flat surface engaging the roll than filaments of the same denier but with a circular cross section. The spreading of the legs causes the filaments to have a greater tendency to adhere to the known draw rolls.

Apparatus corresponding to that in the accompanying drawing was used to treat the yarn. The draw roll had a diameter of 3 inches and a length of 4 inches. There were 8 polished strips and the same number of roughened strips. The width of each polished strip was 1 inch and the width of each roughened strip was /2 inch. Nylon 66 yarn having a spun denier of 4370 and a total number of filaments of 14-0 was supplied to the feed rolls 12 and 13 at 35 yards per minute. From the feed rolls the yarn was led onto and around a stationary snubbing pin one time. The yarn was Wrapped around draw roll 15 and the separator roll 5 times. The yarn left the draw roll at 196 yards per minute. The stretched yarn displayed practically no filament breakage. When a draw roll composed entirely of a polished surface was employed under like conditions, considerable filament breakage was noted. Also when a draw roll composed entirely of a roughened surface was employed under like conditions, the yarn tended to slip undesirably around the draw roll. When a draw roll having a polished proximal end portion and a roughened distal end portion was employed under like conditions, the stretched yarn exhibited more filament breakage than yarn stretched using the present apparatus. In like manner, lower quality yarn was obtained by using a draw roll having roughened strips and polished strips intersecting at right angles.

From the foregoing it is seen that there are numerous advantages afforded by the use of the above-described apparatus. Yarn can be stretched with a minimum filament breaking. The number of wraps taken around the draw roll to hold the yarn under the desired drawing tension is reduced compared to the number required when a roll composed entirely of a roughened surface is used. Other advantages will be noted.

It is to be understood that the invention is not to be limited to the specific embodiments shown and described herein, except as defined in the appended claims.

What is claimed is:

1. Apparatus for drawing textile filaments comprising means to supply textile filaments from a source at a predetermined speed, a cylindrical draw roll adapted to be driven so that the filaments normally being supplied to it are under considerable tension, said draw roll having a plurality of high-friction polished strips and a plurality of low-friction matte strips formed on the peripheral surface thereof, the filaments normally engaging said highand said low-friction strips, said strips being substantially parallel and extending axially of said draw roll, the polished strips and the matte strips following one another alternately about the periphery of said draw roll, the total surface area of the polished strips constituting about 50-80 percent of the total filament engaging peripheral area of said draw roll, and a separator roll mounted adjacent to said draw roll in spaced relationship therewith and positioned so that the axis of said separator roll is disposed at a slight angle with respect to the axis of said draw roll in order that the filaments normally progressing engagingly around said draw roll and said separator roll will describe generally a helix with convolutions being spaced apart.

2. Apparatus for drawing textile filaments comprising means to supply synthetic textile filaments capable of being molecularly oriented from a source thereof at a pre determined speed, a metal cylindrical draw roll adapted to be driven at a peripheral speed greater than the speed at which the filaments are supplied so that the filaments are stretched a predetermined extent, said draw roll having a plurality of high-friction polished strips and a plurality of low-friction matte strips formed on the peripheral surface thereof, the filaments normally engaging said highand said low-friction strips, said strips being substantially parallel and extending axially of said draw roll, the polished strips and the matte strips following one another alternately about the periphery of said draw roll, the total surface area of the polished strips constituting about 60-75 percent of the total filament engaging peripheral area of said draw roll, and a separator roll mounted adjacent to said draw roll in spaced relationship therewith and positioned so that the axis of said separator roll is disposed at a slight angle with respect to the axis of said draw roll in order that the filaments normally progressing engagingly around said draw roll and said separator roll will describe generally a helix with convolutions being spaced apart.

3. Apparatus for drawing textile filaments comprising a driven feed roll assemblage for supplying at a predetermined speed synthetic textile filaments delivered thereto from a source thereof, a metal cylindrical draw roll rotatably mounted in spaced relation near said driven feed roll assemblage and adapted to be driven at a peripheral speed greater than the speed at which the filaments are supplied thereto from said feed roll assemblage so that the filaments are stretched to a predetermined extent, said draw roll having a plurality of high-friction polished strips and a plurality of low-friction matte strips formed on the peripheral surface thereof, the filaments normally engaging said highand said low-friction strips, said strips being substantially parallel and extending axially of said draw roll, the polished strips and the matte strips following one another alternately about the periphery of said draw roll, the total surface area of the polished strips constituting about -80 percent of the total filament engaging peripheral area of said draw roll, a separator roll freely rotatably mounted adjacent to said draw roll in spaced relationship therewith and positioned so that the axis of said separator roll is disposed at a slight angle with respect to the axis of said draw roll in order that the filaments normally progressing around said draw roll and said separator roll will describe a helix with the convolutions being spaced apart, and a non-rotative snubbing pin disposed in the filament path between said feed roll assemblage and said draw roll for localizing the draw point of said filaments.

References Cited in the file of this patent UNITED STATES PATENTS 2,320,891 Ryder June 1, 1943 2,993,260 Boerma et a1. July 25, 1961 3,020,621 Sacks Feb. 13, 1962 3,025,660 Gonsalves Mar. 20, 1962 3,029,993 Russell Apr. 17, 1962 OTHER REFERENCES Howell H. 6.: Friction in Textiles, London, Butterworths Scientific Publication (1959), page 138. 

1. APPARATUS FOR DRAWING TEXTILE FILAMENTS COMPRISING MEANS TO SUPPLY TEXTILE FILAMENTS FROM A SOURCE AT A PREDETERMINED SPEED, A CYLINDRICAL DRAW ROLL ADAPTED TO BE DRIVEN SO THAT THE FILAMENTS NORMALLY BEING SUPPLIED TO IT ARE UNDER CONSIDERABLE TENSION, SAID DRAW ROLL HAVING A PLURALITY OF HIGH-FRICTION POLISHED STRIPS AND A PLURALITY OF LOW-FRICTION MATTE STRIPS FORMED ON THE PERIPHERAL SURFACE THEREOF, THE FILAMENTS NORMALLY ENGAGING SAID HIGHAND SAID LOW-FRICTION STRIPS, SAID STRIPS BEING SUBSTANTIALLY PARALLEL AND EXTENDING AXIALLY OF SAID DRAW ROLL, THE POLISHED STRIPS AND THE MATTE STRIPS FOLLOWING ONE ANOTHER ALTERNATELY ABOUT THE PERIPHERY OF SAID DRAW ROLL, THE TOTAL SURFACE AREA OF THE POLISHED STRIPS CONSTITUTING ABOUT 50-80 PERCENT OF THE TOTAL FILAMENT ENGAGING PERIPHERAL AREA OF SAID DRAW ROLL, AND A SEPARATOR ROLL MOUNTED ADJACENT TO SAID DRAW ROLL IN SPACED RELATIONSHIP THEREWITH AND POSITIONED SO THAT THE AXIS OF SAID SEPARATOR ROLL IS DISPOSED AT A SLIGHT ANGLE WITH RESPECT TO THE AXIS OF SAID DRAW ROLL IN ORDER THAT THE FILAMENTS NORMALLY PROGRESSING ENGAGINGLY AROUND SAID DRAW ROLL AND SAID SEPARATOR ROLL WILL DESCRIBE GENERALLY A HELIX WITH CONVOLUTIONS BEING SPACE APART. 